Face bb for Hollowtech II ?

[FelaKuti]

I have an '80s steel bike which I want to put a road Hollowtech II crankset on. My understanding is that it's necessary to have the bb faced to help smooth operation of the bearings, however my LBS has specifically told me that it's not necessary and to just install the bb as is. How big of a risk is it of early bearing wear if I followed the LBS advice?

[queequeg]

I have an '80s steel bike which I want to put a road Hollowtech II crankset on. My understanding is that it's necessary to have the bb faced to help smooth operation of the bearings, however my LBS has specifically told me that it's not necessary and to just install the bb as is. How big of a risk is it of early bearing wear if I followed the LBS advice?

Bearings are in external cups, which screw into the threaded BB shell. The facing is to ensure the two sides of the shell are aligned so that when you insert the crank, it can go in without putting any stress on the bearings. So, it will really depend on whether you frame is already aligned. I'd assume it is, but getting it fixed shouldn't be a huge issue if it needs doing.

[find_bruce]

Yep - screw the bearings in & see how accurate the face is. I have done it on 3 bikes now - 2 80s steel, 1 naughties aluminium, none of them needed facing

[10speedsemiracer]

Yep - screw the bearings in & see how accurate the face is. I have done it on 3 bikes now - 2 80s steel, 1 naughties aluminium, none of them needed facing

Same as Find_Bruce, have thrown Hollowtech into a random assortment of steelies and a 90s alloy Kennedy, none needed re-facing, all worked perfectly.

Put it in, you'll soon know if there's an issue when you fit the cranks.

[Duck!]

I haven't come across any frames that have needed facing. What is more likely to be beneficial or sometimes necessary is chasing the threads with the appropriate taps, because if they're rough and worn they can bugger the threads on the comparitively soft bearing housings.

[FelaKuti]

Thanks for the replies. It's a high end frame from Japan and the finish is very good, so I'll have a go at installing the bearings without facing the BB.

[Mulger bill]

Only time I've seen it as an issue involved a rough as guts rattle can job.

Bit of stanley knife scrapeage and it went in easy as